The broad, long-term objectives of this Mentored Clinical Scientist Development proposal are to provide the candidate-PI with an extensive background in experimental methodology directed toward characterizing translational control mechanisms. As a young academic vascular surgeon, the candidate-PI has established an ongoing interest in the effects of fluid shear stress on endothelial cell function and how hemodynamic forces interact with humoral influences to determine endothelial phenotype. To date, most of the work in this field has focused on transcriptional control events with less emphasis on mechanisms by which mRNA is translated into protein. This award will equip the candidate-PI with the investigational tools necessary to embark on a sustained inquiry into the effects of fluid shear stress on the processes in endothelial cells that govern translation of mRNA into functional proteins (the immediate goal). The specific aims of the research plan are: (1) characterization of the effects of fluid shear stress on phosphatidylinositol 3-kinase, a proximal intermediate in the dedicated mammalian target of rapamycin (mTOR) translational signaling pathway in endothelial cells; (2) characterization of the role of the mTOR pathway in mediating increased translation induced by shear stress; (3) characterization of the post-transcriptional mechanism by which shear stress inhibits expression of E-selectin by endothelial cells after stimulation with inflammatory cytokines. The proposed studies will familiarize the candidate-PI with a variety of techniques including chromatographic methods applied to phospholipid metabolism, strategies for endothelial transgene expression, polyribosome analysis and methods of detecting and characterizing mRNA-protein interactions. A consultant advisory committee has been assembled that will give the candidate-PI access to experts with experience in each of these areas of investigation. The long-term goal of the project, aside from publishing the results of the proposed studies, is to provide the candidate-PI with the resources necessary to establish an independently funded laboratory focused on mechanisms of translational control in endothelial cells. Such studies will enhance our understanding of how endothelial phenotype is determined, how hemodynamic forces may help produce a vascular-specific response to humoral stimuli and contribute to a molecular explanation of how atherosclerotic lesions become localized to particular regions of the vasculature.